RESUMEN Entre los factores que contribuyen para un correcto desarrollo inicial de las plantas, está el sustrato utilizado, por tanto, el objetivo del presente estudio fue evaluar el efecto del sustrato en la formación inicial y morfología de las raíces de dos especies de maracuyá. El experimento fue realizado en vivero con polisombra de interceptación luminosa (60%), en la Universidad Federal de Goiás (UFG), Regional Jataí, Brasil. Los materiales utilizados fueron maracuyá (Passiflora edulis f. flavicarpa) y el cultivar FB 200 (Flora Brasil). Se utilizaron semillas de frutos recolectados del huerto experimental de la UFG. Se sembraron en tres tipos de sustratos: Suelo I (mezcla de 2 partes de suelo + 1 parte de gallinaza + 1 parte de arena), Suelo II (suelo de barranco) y Bioplant®; se utilizó bolsas perforadas para plántulas con capacidad de 1,5 L. El diseño experimental utilizado fue completamente aleatorio con seis tratamientos, ocho repeticiones y cuatro plántulas por parcela. Después de 30 días de siembra, se evaluó: peso fresco de la raíz, peso seco de raíz y morfología de la raíz. El sustrato tuvo efecto en el desarrollo inicial de las plantas de maracuyá, donde se obtuvo los mejores resultados con Bioplant®. Este sustrato sobresalió en todas las características evaluadas mostrando su potencialidad en la propagación de esta especie.

ABSTRACT Among the factors that contribute to better initial development of plants, it is the substrate used. Therefore, this study aimed to evaluate the effect of substrate in initial formation and morphology of the roots of two species of passion fruits. The analyses were done in the nursery of the Federal University of Goiás (UFG), Regional Jataí, Brazil, with a light interception of 60%. The material used were seeds of yellow passion fruit (Passiflora edulis f. flavicarpa) and the cultivar FB 200 (Flora Brasil), harvested in the UFG experimental field. They were sown in three types of substrates: Soil I (mixture of soil, chicken manure and sand in a ratio of 2:1:1 by volume), soil II (steep bank), and Bioplant®, using for plants perforated bags with a capacity of 1.5 L. The experimental design was a completely randomized design with six treatments, eight replications and four plants per plot. After 30 days of sowing, fresh matter of root, root dry matter and morphology were evaluated. The substrate affected the initial development of yellow passion fruit, obtaining the best results with Bioplant®, showing as promising for the development of all the evaluated characteristics.

Three trials were carried out to determine energy metabolized (EM) requirement model for starting and growing pullets from different strains, at five ambient temperatures and different percentage feather coverage. In Trial I, metabolizable energy requirements for maintenance (MEm) and efficiency of energy utilization were estimated using 64 birds of two different strains, Hy-Line W36 (HLW36) and Hy-Line Semi-heavy (HLSH), from 9 to 13 weeks of age. The effects of ambient temperature (12, 18, 24, 30 and 36ºC) and percentage feather coverage (0, 50 and 100%) on MEm were assessed in the second trial, using 48 birds per temperature per strain (HLSH and HLW36) from 9 to 13 weeks of age. Trial III evaluated ME requirements for weight gain (MEg) using 1,200 birds from two light strains (HLW36 and Hisex Light, HL) and two semi-heavy strains (HLSH and Hisex Semi-heavy, HSH) reared until 18 weeks of age. According to the prediction models, MEm changed as a function of temperature and feather coverage, whereas MEg changed as a function of age and bird strain. Thus, two models were developed for birds aged 1 to 6 weeks, one model for the light strain and one for the semi-heavy strain. Energy requirements (ER) were different among strains from 7 to 12 weeks, and therefore 4 models were elaborated. From 13 to 18 weeks, one single model was produced for semi-heavy birds, since ER between semi-heavy strains were not different, whereas two different models were elaborated for the light layers. MEg of light birds was higher than MEg of semi-heavy birds, independent of age.

Um modelo polinomial segmentado foi usado em diversas curvas de produção de ovos, numa tentativa de analisar as diferenças entre as curvas de um modo mais descritivo. Foram usadas curvas de produção de diferentes linhagens comerciais e experimentais de poedeiras. Os parâmetros do modelo incluem a idade e nível do pico de produção, a taxa de decréscimo na produção após o pico e o tempo entre o início e o pico de produção. Essas e outras variáveis derivadas pelo modelo foram comparadas entre as curvas usando contrastes. A metodologia usada facilitou a interpretação das curvas e a detecção de diferenças na maturidade sexual, uniformidade e pico de produção. Esse trabalho valida o modelo de polinômios segmentados para uso em pesquisas futuras que tratem de análise de curvas de produção de ovos.

A segmented polynomial model was used on several egg production curves in an attempt to analyze the differences between the curves in a more descriptive manner. Production curves from different commercial and experimental genetic lines of layers were used. The parameters of the model include the age and level of peak production, rate of decrease in production after the peak and time between start and peak of production. These and other derived variables were compared between the curves using contrasts. The methodology used allowed an easier interpretation of the curves, and the detection of differences in sexual maturity, uniformity and peak of production. This work validates the segmented polynomial model for use in future research dealing with analysis of egg production curves.